Lu Yen-hsun is a former Taiwanese tennis player. He holds the record for most singles wins on the ATP Challenger Tour, with 29 singles titles in his career. He also boasts three ATP Tour doubles titles and 13 Challenger titles.
His best positions in the ATP rankings were 33rd in singles in November 2010 and 86th in doubles in January 2005. His best result in Grand Slam trials was the quarterfinal reached in singles at the 2010 Wimbledon tournament. 2014 loses the only final played on the major circuit in singles.
After ten defeats in singles in the quarterfinals of ATP tournaments, in January 2014 he reached a semifinal for the first time in Auckland thanks to successes over Igor Sijsling, Bradley Klahn and in the quarterfinals over Steve Johnson. In the semifinal he surprisingly beat world No. 3 David Ferrer in two sets and, in the only final played in singles in his career, he lost after two tie breaks to John Isner.
He retired in 2021.